An efficient ultrasound promoted catalyst-free protocol for the synthesis
J VENKATA PRASAD, J SATYANARAYANA REDDY, N RAVI KUMAR,
K ANAND SOLOMON and G GOPIKRISHNA*
Sankar Foundation Research Institute, Visakhapatnam 530047, India
MS received 31 December 2010; revised 24 May 2011; accepted 30 May 2011
Abstract. A convenient, catalyst-free protocol for the quantitative synthesis of fused chromeno[4,3-
b]quinolin-6-ones has been developed by simple one-pot reaction of substituted anilines with 4-chloro-3-
formylcoumarin using ultrasound irradiation. The protocol offers the advantages of mild reaction conditions,
short reaction times and high yields.
Graphical Abstract. Tetracyclic chromeno-quinolines are precipitated as pure products from the
reaction of 4-chloro-3-formyl-coumarin and aromatic anilines in ethanol under
Keywords. Ultrasound; 4-chloro-3-formylcoumarin; anilines; chromeno-quinoline.